Manufacture of dentures and the like



Patented Jan. 25,1927 7 UNITED STATES P rEuroFI-"icE.

anonrn nronnr. BUBLIN, or LONDON, ENGLAND, ASSIGNOR or ONE-THIRD mo SHEL- DON LEICESTER AND ONE-THIRD T LEONARD HOLMAN, BOTH OF- L0N- DON, ENGLAND.

MANUFACTURE OF DENTUBESAND THE LIKE.

No Drawing. Application filed February 5, 1926, Serial No. 86,346, and in Great Britain February 11, 1925.

Attempts have been made to employ nitro-' cellulose compositionsdn substitutlonfor the materials referred to, but it has been found that nitrocellulose (or its plastics) is unsuitable for usegexcept. in the manufacture of dentures for exhibition in show-cases or the like.

Vulcanite, which is the material most extensively used in the manufacture of dentures, has certain. disadvantages. It is, for

instance, brittle and liable to fracture and desired colour and rivative a cellulose acetate may be specified.

is found to irritate the gumsof certain sub ects.

According to the present invention, in the production of dentures and the like, .water insoluble organic derivatives of cellulose, capable of being .i'noulded in a granular or pulverulent form, are introducedinto a heated mould the two halves of which are brought together under the action of pressure.

Normally the materials in question will be used in combination with bodies adapted to act as plasticizers or colloiding agents and as colloiding agents or plasticizers, bodies which are substantially tasteless and odourlem must be used.

In carrying the invention into effect, cellulose acetate in, association with known colloidini agents, such as benzyl alcohol, benzoin, enzil pr triacetin, in a proportion of 25 parts of, colloiding agent to 75 parts of cellulose acetate together with a sufli-' cient proportion of a pigment to secure the opacit may beu'sed. As an example of-a sultable cellulose de In forming from cellulose acetate, or the like, compositions in accordance with the invention for use in the manufacture of dentures and the like, a proportion of a suitable plasticizing agent adapted to enable the material to be moulded-under heat in the absence of added volatile be employed.

For colouring the composition white tisolvents v avill tanium pigments in association with vermilion or other suitably coloured pigments may be used.

. Thus in accordance with the invention, the-case of teeth embedded in wax is inserted into the flask in the reverse direction from that in which the case of teeth is inserted therein when using vulcanite. In other words, the teeth have the biting, sur- 1 face inserted in the-plaster.

The flask is finished in the usual manner,

removed in the usual way.

The two halves of the flask after heating 7 containing the teeth, and the said lial-fwith the cellulose ester mass therein heated to the desired temperature in a press under direct dry heat.

' Whenthe temperature of the flask register's-160 C. or thereabouts (it should not opened when the plaster has setand the wax 6 5 exceed 200- C.) the two'halves of the flask are brought together and pressure is gradually applied until the flask is completely closed. This' operation may take about fifteen minutes. So soon as the flask is completely closed' it is placed in cold water where it is allowed to remain until quite cold.

The flask is then opened and the case removed, the surplus material being trimmed off and the case finished in the usual manner.

.. .With the material employed in'accordplate so' prepared removed intact, ,inserted Y in plaster in a repairing flask, a piece of the cellulose derivative composition inserted and the flask introduced into I and treated in the press as above descrlbed.

Preferably, a dove-tailed slot or the like I claim: 15

is cut in the plate of the existing denture A denture comprising artificial teeth and in order to assist further in securing satisa, moulded composition containing waterfactory connection between it and the added insoluble organic derivatives of cellulose 5 portion. conforming with the shape of the jaw with 1 Optionally, the connection between the rewhich the denture is to be associated. 2 placed and the original portion is effected In testimony whereof I have signed my by the employment of suitable volatile solname to this siecificat-ion. vents. ADO PH LIONEL BURLIN 

